The major purposes of the proposed research are (a) to examine the potential contributions over time of individual differences in various types of effortful control (EC, including the abilities to inhibit a dominant response and/or to activate a subdominant response, to plan, and to detect errors) and reactive (less voluntary) control (RC) to young children's adjustment, emotionality/cortisol reactivity, social and academic competence, social cognition, and personality resiliency, and (b) to examine the associations of both parenting (e.g., expression of emotion, sensitivity, warmth, reactions to children's negative emotions) and heredity (using genes linked to EC and/or adjustment) to children's regulation/control and adjustment, and if social support, stress, or some types of parenting moderate these relations for heredity. We expect (a) low attentional and activational EC, low resiliency, involuntary overcontrol, and proneness to fear/sadness to be predictors of at least some types of internalizing problems;(b) low RC, low EC and high anger/frustration to predict externalizing problems;(c) relations of EC to vary with the type of internalizing symptoms and with age, (d) resiliency to mediate relations of EC to internalizing problems and social competence, (e) cortisol/salivary alpha-amylase (sAA) responding to relate to measures of emotional reactivity, (mal)adjustment, and low EC, (f) links of EC and/or RC to social and academic functioning, (f) relations between a range of developmental outcomes and EC to become stronger with age in the early years of life, (g) relations of parenting to adjustment to be mediated by EC, and (h) relations of specific candidate genes with EC and adjustment (perhaps moderated by environmental factors). A multi-method (e.g., behavioral measures, questionnaires, genes), multi-reporter approach will be used in 3 assessments to extend a study of children from age 18 to 48 months through age 7. The aforementioned variables, as well as family-level variables (stress, SES, marital functioning), will be assessed;earlier assessments include a rich assortment of indices of EC, RC, emotionality, language, adjustment, and parenting. These data would allow tests of the joint and unique relations of EC, RC, parenting, and genes to adjustment from toddlerhood to school age. Thus, the proposed work focuses on both the biological and environmental bases of young children's mental illness (including internalizing and externalizing problems) and mental health (socio-emotional functioning).The proposed work would examine the emergence of a range of mental health problems in children, including externalizing problems such as symptoms/diagnosis of conduct disorders, inattention problems, and oppositional/defiant behavior and internalizing problems such as depressed affect and generalized anxiety. The work would also examine relations of emotionality and emotion-related self-regulation, children's emotion understanding, quality of parenting, and biological (cortisol) and genetic predictors of adjustment and general quality of socioemotional functioning to adjustment. Novel components of the work include the longitudinal nature of the study (from toddlerhood to school age), the strong focus on processes related to regulation, the focus on genetic predictors of adjustment, and examination of the joint prediction of adjustment from heredity and environmental factors (e.g., stress, parenting).